Prior to the present invention, there has existed an ever-increasing hazard in the use of pressurized commercial tanks for the transporting of caustic and/or explosive gases, which tanks are devoid of any safety-valve feature what-so-ever often, and in other situations, the nature of the safety-valve is subject to the same hazards in the event of an accident resulting in an impact or blow to the outlet conduit or safety-lock-containing portion thereof. The criticality of the situation has increased by many fold recently--in recent years and months, during which gaseous fuels are transported in large trucks and tanks and railroad cars and the like; but particularly, there is now underway the manufacture of motor vehicles driven by pressurized inflammable gas which carry the fluid gas within pressurized tanks a part of the vehicle itself, subject to explosion or at-least to flash-fire and destruction of life and/or property within the vehicle as well as to those in the immediate vicinity.
While heretofore such situation has not been remedied, and the extreme hazards associate have not been loudly proclaimed, the sole existing prior art that has thus far been available is typified by U.S. Patents such as follow. Each of U.S. Pat. Nos. 1,525,775 (W. E. Floyd et al.) and 1,136,606 (M. W. Loyd et al.) and 2,765,801 (F. E. Selim) have portions of the valve-guidable structure and shaft-like structure thereof extending "past" the point of the tank wall of the port into which the valve has been screw-mounted, with the result that any major blow readily would likely impair proper axial movement thereof thus preventing the safety valve from becoming properly seated in its valve seat. Accordingly, such safety or lock valves are not destruction-proof by accidents as often occur in highway-driven motor vehicles, nor for presurized tanks being otherwise transported by truck or rail. Further examples of such prior safety or lock-valves are those of U.S. Pat. Nos. 3,159,167 and 1,513,020 and 2,563,244 each of which either have all or a major portion thereof exterior to the port-forming walls of the pressure tank. By such valves, any traffic accident could readily cause a leak--major or minor, either of which could lead to explosion, fire, or the breathing of deadly gas fumes.